Many approaches exist to cataloging or indexing documents and making them available as part of a collection to users. Simple search systems, for example, allow for the selection of documents based on text (keyword) searching.
Other approaches may involve the use of taxonomy-based methodologies to classify documents into certain categories. In these approaches, taxonomies of the domain are defined and documents are tagged or sorted into categories in accordance with the relevance of these documents to elements of the defined taxonomies. While this is useful for organizing or classifying a collection of documents, it does little to increase their searchability if they are not sorted using categories appropriate to the search context being used. Furthermore, this does little to improve the ability of a user or system being able to perform analysis on the documents.